阅读说明：本技术 一种用于井中雷达的定向天线系统 (Directional antenna system for radar in well ) 是由 赵青 童继生 郭成 赵怿哲 李佳黛 刘耀耀 于 2021-08-17 设计创作，主要内容包括：本发明公开了一种用于井中雷达的定向天线系统,属于井中雷达技术领域。本发明的定向天线系包括天线单元(1)、玻璃钢管(2)、天线保护壳(3)、填充液(4)、射频开关(5)和十字形金属结构(6)；玻璃钢管(2)位于天线保护壳(3)内,玻璃钢管(2)内部注入有填充液(4),多个天线单元(1)等间隔分布于玻璃钢管(2)的外侧壁且与玻璃钢管(2)共形,各天线单元(1)与玻璃钢管(2)的中心轴的间距相同；天线单元(1)之间设置有与玻璃钢管(2)共形的金属阵列结构,金属阵列结构包括至少两排沿玻璃钢管(2)的中心轴方向排列的十字形金属结构(6),十字形金属结构(6)之间以及十字形金属结构(6)与相邻的天线单元(1)之间通过射频开关(5)相连。本发明提供的定向天线系的体积小,具备超宽带、高辐射效率特性,波束扫描的能力和井下工作的能力。(The invention discloses a directional antenna system for an in-well radar, and belongs to the technical field of in-well radars. The directional antenna system comprises an antenna unit (1), a glass fiber reinforced plastic pipe (2), an antenna protective shell (3), filling liquid (4), a radio frequency switch (5) and a cross-shaped metal structure (6); the glass fiber reinforced plastic pipe (2) is positioned in the antenna protective shell (3), filling liquid (4) is injected into the glass fiber reinforced plastic pipe (2), the antenna units (1) are distributed on the outer side wall of the glass fiber reinforced plastic pipe (2) at equal intervals and are conformal with the glass fiber reinforced plastic pipe (2), and the distance between the antenna units (1) and the central axis of the glass fiber reinforced plastic pipe (2) is the same; be provided with the metal array structure conformal with glass steel pipe (2) between antenna element (1), metal array structure includes two row at least cross metal structure (6) of arranging along the center pin direction of glass steel pipe (2), links to each other through radio frequency switch (5) between cross metal structure (6) and adjacent antenna element (1). The directional antenna system provided by the invention has small volume, and has the characteristics of ultra wide band and high radiation efficiency, and the capability of beam scanning and the capability of underground working.)

1. A directional antenna system for a radar in a well is characterized by comprising an antenna unit (1), a glass reinforced plastic pipe (2), an antenna protective shell (3), filling liquid (4), a radio frequency switch (5) and a cross-shaped metal structure (6);

the glass fiber reinforced plastic pipe (2) is positioned in the antenna protective shell (3), and filling liquid (4) is injected into the glass fiber reinforced plastic pipe (2);

the antenna units (1) are distributed on the outer side wall of the glass steel tube (2) at equal intervals, the distance between each antenna unit (1) and the central axis of the glass steel tube (2) is the same, and the antenna units (1) are conformal to the glass steel tube (2);

be provided with metal array structure between antenna element (1), and metal array structure and glass steel pipe (2) conformal, metal array structure includes two row at least cross metal structure (6) of arranging along the center pin direction of glass steel pipe (2) to link to each other through radio frequency switch (5) between cross metal structure (6) and adjacent antenna element (1), switch on through control radio frequency switch (5), make antenna element (1) take over work.

2. A directional antenna system according to claim 1, characterized in that the antenna element feed point (1-1) of the antenna element (1) is located in the middle of the antenna element (1).

3. A directional antenna system according to claim 1, characterized in that the cruciform metal structure (6) located at the ends of the metal array lacks a lateral branch and is in a transverse "T" configuration.

4. The directional antenna system according to claim 1, characterized in that the width of the antenna unit (1) is set to 5-15mm and the length is set to 5-15mmWherein epsilon_effThe effective dielectric constant of the surrounding material of the antenna element (1) is indicated, and f indicates the operating frequency of the directional antenna system.

5. Directional antenna system according to claim 1, characterized in that the inner diameter R of the glass-reinforced plastic tube (2)₁And outer diameter R₂Is in millimeters, and satisfies: r is more than or equal to 32₁≤R₂-5≤42.5。

6. A directional antenna system according to any one of claims 1 to 5, characterized in that the dimensions of the cross-shaped metal structure (6) are:

definition 2x represents the length of the cross-shaped metal structure (6) parallel to the central axis of the glass fiber reinforced plastic pipe (2), definition y represents the length of the cross-shaped metal structure (6) perpendicular to the central axis of the glass fiber reinforced plastic pipe (2), and satisfies:

wherein l and w respectively represent the length and width of the antenna unit (1), and R₂The outer diameter of the glass fiber reinforced plastic pipe (2) is shown.

7. The directional antenna system according to claim 1, wherein the relative dielectric constants of the glass fiber reinforced plastic tube (2) and the antenna protective housing (3) are both: 3 to 6.

8. The directional antenna system according to claim 1, characterized in that the relative dielectric constant of the filling liquid (4) is 60-80.

9. A directional antenna system according to claim 1, characterized in that the number of antenna units (1) is four, respectively in the direction of 0 °, 90 °, 180 ° and 270 ° of the glass-reinforced plastic tube (2).

10. A directional antenna system according to claim 1, characterized in that the radio frequency switch (5) is a PIN diode.

Technical Field

The invention relates to the technical field of in-well radars, in particular to a directional antenna system for an in-well radar.

Background

The radar in the well is an important branch of the ground penetrating radar, and is widely applied to the fields of petroleum mineral exploitation, archaeological excavation, underground pore exploration, underground karst cave measurement and the like as a quick and nondestructive measurement mode. Because the radar in the well works in the well hole, compared with the ordinary ground penetrating radar, the radar in the well needs to have the characteristics of the ordinary ground penetrating radar, and also needs a small-sized radar system and a watertight characteristic.

The performance of the antenna, which is one of the key components of the radar system, directly affects the radar detection performance. In view of the size limitation of the radar in the well, most of the radars in the well adopt a traveling wave dipole antenna loaded by resistors, and the antenna has a slender shape and an ultra-wide working bandwidth and meets the performance requirement of the radar in the common well. However, it is an omnidirectional antenna, so that it is difficult to obtain azimuth information of a target during a detection process, and the target cannot be three-dimensionally positioned. But acquisition of the orientation information of the target is very important in engineering exploration. In order to acquire azimuth information of a target, scholars at home and abroad put forward various schemes, specifically, the two schemes can be summarized, one scheme is to design a directional antenna, a plurality of directional antennas are arrayed along the axial direction, the main lobe direction of each directional unit is different, and the units with different main lobe directions complete 360-degree coverage in a well. Thus, although the angle information of the target can be obtained, since all the units are in different planes, the three-dimensional positioning of the target is difficult. And the other method is to utilize four omnidirectional antennas on the same plane, and acquire azimuth angle information of the target by analyzing the amplitude and phase difference of echo signals received by the four antennas. However, the difference of signals received by the four antennas is not obvious because the four antennas are too close to each other, and the interference between the antennas is large, so that the realization difficulty is high.

Therefore, the design of the directional antenna system for the radar in the well, which has small interference among units and all the units in the same plane, is very favorable for obtaining the azimuth angle of the target during radar detection in the well.

Disclosure of Invention

The invention provides a directional antenna system for a radar in a well, which has a small volume and also has a beam scanning function.

The technical scheme adopted by the invention is as follows:

a directional antenna system for a radar in a well comprises an antenna unit, a glass reinforced plastic pipe, an antenna protective shell, filling liquid, a radio frequency switch and a cross-shaped metal structure;

the glass fiber reinforced plastic pipe is positioned in the antenna protective shell, and filling liquid is injected into the glass fiber reinforced plastic pipe;

the antenna units are distributed on the outer side wall of the glass steel tube at equal intervals, the distance between each antenna unit and the central axis of the glass steel tube is the same, and the antenna units are conformal with the glass steel tube;

the antenna comprises antenna units, and is characterized in that metal array structures are arranged between the antenna units and are conformal with the glass steel tube, each metal array structure comprises at least two rows of cross-shaped metal structures arranged along the central axis direction of the glass steel tube, the cross-shaped metal structures are connected with adjacent antenna units through radio frequency switches, and the antenna units are enabled to work alternately by controlling the conduction of the radio frequency switches, namely when a specified antenna unit works, the rest antenna units and the metal array structures between the rest antenna units are conducted to form a metal reflecting surface.

By adopting the technical scheme, the cross-shaped metal structure is arranged between the antenna units and is conformal with the glass fiber reinforced plastic pipe, so that the adjacent antenna units of the cross-shaped metal structure realize the characteristics of ultra wide band and high radiation efficiency under the action of the cross-shaped metal structure. The antenna system has the capability of beam scanning through the conduction of the radio frequency switch. Filling liquid is injected into the glass fiber reinforced plastic pipe, the pressure of the glass fiber reinforced plastic pipe in a well is balanced by the filling liquid, and the volume of the antenna is reduced by utilizing the characteristic of high relative dielectric constant of the filling liquid. An antenna protective shell is arranged outside the antenna and used for protecting the antenna from being damaged by substances in the well during well logging. Thereby enabling the antenna system to be capable of downhole operation.

Furthermore, the antenna element feed point of the antenna element is located in the middle of the antenna element.

Furthermore, the cross-shaped metal structures at the head end and the tail end of the metal array structure lack a lateral expending end and are in a transverse T-shaped structure.

Furthermore, the width of the antenna unit is set to be 5-15mm, and the length of the antenna unit is set to be 5-15mmWherein epsilon_effRepresenting the effective dielectric constant of the surrounding material of the antenna element, and f representing the operating frequency of the directional antenna system.

Further, the inner diameter R of the FRP pipe₁And outer diameter R₂Is in millimeters, and satisfies: r is more than or equal to 32₁≤R₂-5≤42.5。

Further, the size of the cross-shaped metal structure is as follows:

definition 2x represents the length of the cross-shaped metal structure parallel to the central axis of the glass reinforced plastic pipe, and definition y represents the length of the cross-shaped metal structure perpendicular to the central axis of the glass reinforced plastic pipe, and satisfies:wherein l and w respectively represent the length and width of the antenna element, and R₂The outer diameter of the glass fiber reinforced plastic pipe is shown.

Further, the number of the antenna units is four, and the antenna units are respectively positioned in the directions of 0 °, 90 °, 180 ° and 270 ° of the glass fiber reinforced plastic tube).

Further, the radio frequency switch is a PIN diode.

In summary, the technical scheme provided by the invention at least has the following beneficial effects:

(1) the antenna system has the capability of beam scanning by controlling the conduction of the radio frequency switch;

(2) the antenna system has the capability of working underground;

(3) the antenna adopts a conformal technical means and fills liquid in the filled glass fiber reinforced plastic tube to ensure that the antenna has compact structure and small volume;

(4) the antenna units of the antenna system are in the same plane, and each unit has high directional characteristic, so that azimuth angle information of a target can be conveniently acquired during radar measurement in a well.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a cross-sectional view of a directional antenna system for a radar in a well according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a directional antenna system for a radar in a well provided by an embodiment of the present invention;

FIG. 3 is a tiled, expanded view of a directional antenna system for an in-well radar provided by an embodiment of the present invention;

FIG. 4 is a return loss plot of a directional antenna system for an in-well radar provided by an embodiment of the present invention;

fig. 5 is a radiation pattern of a directional antenna system for a radar in a well according to an embodiment of the present invention.

Reference numerals:

1-antenna unit, 1-antenna unit feed point, 2-glass fibre reinforced plastic pipe, 3-An antenna protection shell, 4-filling liquid, 5-radio frequency switch, 6-cross-shaped metal structure, 2 x-length of the cross-shaped metal structure, y-width of the cross-shaped metal structure, l-length of the antenna unit, w-width of the antenna unit, R₁Inner diameter of FRP pipe, R₂Outer diameter of FRP pipe, R₃-the antenna protective housing outer diameter.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to fig. 1 to 3, a directional antenna system for a radar in a well according to an embodiment of the present invention includes: the antenna comprises an antenna unit 1, a glass steel tube 2, an antenna protective shell 3, filling liquid 4, a radio frequency switch 5 and a cross-shaped metal structure (6); in a preferred manner, in the present embodiment, the rf switch 5 employs a PIN diode.

Wherein, the filling liquid 4 is filled in the glass fiber reinforced plastic pipe 2 to balance the external pressure to which the glass fiber reinforced plastic pipe is subjected during well logging. The filling liquid 4 adopts liquid with high relative dielectric constant (preferably 60-80 relative dielectric constant), so as to reduce the working frequency of the antenna and realize the miniaturization of the antenna; the glass fiber reinforced plastic pipe 2 has high mechanical strength, and in this embodiment, the glass fiber reinforced plastic pipe 2 has a relative dielectric constant of 3-6 and an inner diameter R₁The external meridian is R₂And satisfies R of 32mm or less₁≤R₂The thickness is less than or equal to-5 mm and less than or equal to 42.5mm, so that the antenna system has strong mechanical property while ensuring the electrical property of the antenna system to adapt to the harsh environment in a well; the antenna units 1 are distributed on the outer side wall of the glass fiber reinforced plastic pipe 2 at equal intervals, the distance between each antenna unit 1 and the central axis of the glass fiber reinforced plastic pipe 2 is the same, and the antenna units 1 are conformal to the glass fiber reinforced plastic pipe 2; the antenna protection shell 3 needs to have strong wear-resistant and corrosion-resistant properties, and in this embodiment, the relative dielectric constant is set to be 3-6, and the outer diameter R is set to be₃≤44.5mm；

Set up the metal array structure between antenna element 1, and the metal array structure is conformal with glass steel pipe 2, and this metal array structure includes two row at least cross metal structure 6 of arranging along the center pin direction of glass steel pipe 2 to link to each other through radio frequency switch between the cross metal structure 6 and between cross metal structure 6 and the adjacent antenna element 1, switch on through control radio frequency switch, make antenna element take over work.

Preferably, the number of the antenna units 1 is 4, the antenna units are respectively arranged at 0 °, 90 °, 180 ° and 270 ° outside the glass fiber reinforced plastic tube 2 and are conformal with the glass fiber reinforced plastic tube 2, the width w of the antenna unit 1 is 5-15mm, and the length l is taken asf denotes the operating frequency of the directional antenna system, ε_effIs the effective dielectric constant of the material surrounding the antenna element 1.

Referring to fig. 3, a preferred way is to remove the extending end of one side surface of the cross-shaped metal structure 6 at the head and tail ends of the metal array structure, so that the metal array structure is in a transverse T-shaped structure, so that the two side surfaces of the metal array structure are in a linear shape. Preferably, the length of the cross-shaped metal structure 6 conformal with the glass steel tube 2 is 2x, the width thereof is y, the length and the width satisfy 2x ≤ l/9, and y<(2πR₂-4 w)/8. The PIN diode is used to connect the adjacent cross-shaped metal structure 6 and the cross-shaped metal structure 6 with its adjacent antenna element 1.

For example, for the case that the number of the antenna elements 1 is 4, the four antenna elements 1 have the same structure and are reciprocally located, the antenna element feed point 1-1 is located in the middle of the antenna element 1, each antenna element 1 is an element of the antenna system, and the four antenna elements 1 take over to receive or transmit signals when the antenna system is in operation. The adjacent cross-shaped metal structures 6 and the cross-shaped metal structures 6 are connected with the adjacent antenna units 1 through PIN diodes, and the antenna units 1 are enabled to take over work by controlling the on-off of the PIN diodes, so that beam scanning of the antenna system is realized. As shown in fig. 3, for example, when the antenna unit 1 at 0 ° is operated, the PIN diodes installed between the antenna units 1 at 0 ° and 90 ° and 270 ° are all turned off, and the PIN diodes installed between the antenna units at 180 ° and 90 ° and 270 ° are all turned on, so that the antenna units 1 at 90 °, 180 ° and 270 ° and the cross-shaped metal structure 6 therebetween are guided to form a metal reflection surface, and the antenna unit at 0 ° is operated, and further the main lobe direction of the antenna system is 0 °, and the return loss and the radiation pattern thereof are respectively shown in fig. 4 and 5. Since the four antenna units 1 have the same structure and are reciprocal in position, when the main lobe direction of the antenna system is controlled to face 90 °, 180 ° and 270 °, the return loss and the radiation pattern shape of the antenna system are the same as those in fig. 4 and 5. And similarly, the PIN diode is controlled to enable the main lobe direction of the antenna system to face 90 degrees, 180 degrees and 270 degrees, so that the 360-degree beam scanning of the well circumference of the antenna array is realized.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.